SFTPD Human

Surfactant Protein D (SP-D) is a crucial component of the pulmonary surfactant system, which plays a vital role in maintaining lung function and host defense. SP-D belongs to the collectin family of proteins, characterized by their collagen-like regions and carbohydrate recognition domains. In humans, SP-D is encoded by the SFTPD gene and is primarily synthesized by alveolar type II cells and Clara cells in the lungs .

SP-D is a C-type calcium-dependent lectin that forms a trimeric structure, with each subunit consisting of an N-terminal domain, a collagenous region, a nucleating neck region, and a C-terminal lectin domain . These trimers further assemble into a tetrameric complex, which is essential for its biological functions .

The primary function of SP-D is to participate in the innate immune defense of the lungs. It helps clear infectious pathogens, modulates the immune response, and maintains surfactant homeostasis . SP-D has shown an anti-inflammatory role by down-regulating the release of pro-inflammatory mediators and decreasing the recruitment of inflammatory cells to the lung .

Recombinant human SP-D (rhSP-D) has been successfully produced to mimic the structure and functions of native SP-D. This recombinant form is used in various in vitro and in vivo experiments to study its potential therapeutic applications .

Several studies have demonstrated that treatment with rhSP-D can reduce lung inflammation caused by different insults. This has led to the exploration of rhSP-D as a potential treatment for bronchopulmonary dysplasia (BPD), a rare disease in preterm infants characterized by lung inflammation and tissue injury . The administration of rhSP-D has shown promise in preventing BPD by inhibiting lung tissue injury and improving pulmonary outcomes in preterm infants .